''Puratasi month'' (September - October) fasting - what are the benefits?

Fasting quote. bukrate.com

During certain Hindu festivals fasting is an integral part of  a ritual commonly associated with Gods such as Vishnu, Shiva, Karthikeya (Muruga) and Goddess Lakshmi or Mariamman.  From health point of view fasting or Vriata is good. The entire body including the heart takes rest. Particularly, heart and other parts of the body have been active since birth of a person, so they need a break once in a while.

What is fasting?  It is  a willful  act refraining  from eating and sometimes just  drinking water and Juice). From a purely physiological  context, it refers  to the metabolic condition  of a person who has not taken overnight  or to the metabolic state achieved after complete digestion and absorption of a meal.  During fasting the body undergoes several  metabolic adjustments. It all depends on the duration of fasting.  However,  fasting state begins only after  absorption of a meal (typically 3–5 hours after eating).

Fasting. picturequotes.com

Fasting, a type of 'kayika (physical) ''vrita'' (vow) is an optional part of  Hinduism. Contrary to many other religious fasting, in Hinduism, normally a strict diet is recommended  during the fasting period as opposed to completely giving  up food. The fasting may be a strict one where by the person gives up  food and  fluid completely. This type of fasting  is done on occasions.

It is believed that  fasting will help a person  focus more on  God,  cleanse his mind and body, develop mental prowess to engage in various phases of  life - sacraments called saṃskāras and concentrate on ways and means to get rid of  negative forces.  Saints believe fasting is one of the steps to create a link between body and soul. This blending is imperative for the nourishment of spirituality. 

By way of fasting we  can  reduce  over work to our body, gain patience,  control emotional  as well as mental-well being and quietly use discretionary power during hard times.  

Gandhiji on fasting. azquotes.com

Among fasting Shivaratri, Vaikunta Ekadasi and Puratasi virta assumes  due importance. especially, the latter is observed in the Tamil month of Puratasi (September- October).

Why is  Puratasi month (September 17 and ends on October 17) chosen for fasting?  The traditional belief has been that God Vishnu  (Lord Venkateswara /Balaji) appeared on the earth in this month. Yet another reason is Puratasi Saturdays  are chosen to worship Shani Baghawan  who is supposed to be a powerful  planet (astrologically) causing hardship to humans who are under his spell.  Fasting on Saturdays in this month will, it is believed, will reduce the  bad effects on the affected people or nullify them.  It is well and good if people  observe partial fasting (skipping night meal) through out the month.  

Further,  the advantage of  fasting in this month is  Shani's power will be at the minimum and it is easy to please him.  Lighting earthen lamps with gingerly oil or  Ghee  in the Navagriha shrine or at home is  good to  subdue the effects of Shani. 

Some ardent devotees observe strict adherence to fasting on Saturdays. Not even a drop of water is taken the whole day. 

Apart from taking only vegetarian food,  taking head bath in the early morning is a must before starting the Vrita. For the followers of Vishnu,  meditation on God Balaji is a must; so is the wearing of  Thirumun (Namam- Vaishnavite  religious symbol) on the forehead symbolic of total surrender to the almighty. Of course, the edit of God can never be changed, but the lord will protect those who  take refuge in him. 

Chanting certain mantras while on fast will help you calm you down and relax your mind; regular practice of fasting along with meditation will take you on a higher spiritual plane. 

A few words of caution: Those who have diabetes severe problem  or heart  problem should consult a physician before opting for fasting. Continuous  strict fasting more than   one and half days will drastically affect the health.  After prolonged fasting, if a person takes a sumptuous meal, there will be sudden gain in sugar level that might lead to health  complications. In every aspect of life, moderation is a good bet.  

https://en.wikipedia.org/wiki/Fasting#Vedas

https://www.hindu-blog.com/2009/09/puratassi-fasting-puratasi-vratam.html

https://civilservice.blog.gov.uk/wp-content/uploads/sites/86/2019/10/hindu-fasting-in-the-workplace-awareness-guide-1.pdf